Instructions

1. In a large bowl, combine the flour, 2 tablespoons of brown sugar and 1 teaspoon of the salt. Cut the butter into cubes and add it to the flour mixture, along with the shortening. Use a pastry cutter or a fork to cut the butter and shortening into the flour until it forms coarse crumbs. Gradually add the ice water, adding just enough until the mixture can be pressed together with your fingers. Press into a disc and wrap tightly with plastic wrap. Refrigerate for at least 1 hour. (Can be prepared a day ahead.)
2. Preheat the oven to 400ºF.
3. In a large bowl, combine the peaches, remaining 3/4 cup brown sugar, cornstarch, lemon juice, cinnamon, nutmeg and 1/4 teaspoon of the remaining salt. Stir gently to combine, then let sit for 30 minutes.
4. Remove the pastry from the refrigerator and roll into a 13-inch circle on a lightly floured surface. Transfer the rolled pastry to a 10-inch cast iron skillet. Using a slotted spoon, transfer the peaches to the skillet. Reserve the remaining liquid. Fold the edges of the pastry over the filling, leaving the center uncovered. Pleat the edges of the pastry as needed. Brush the egg over the pastry, then sprinkle with the coarse sugar.
5. Bake the pie until the edges of the crust are golden brown and the filling is bubbling, 45-55 minutes.
6. Combine the reserved liquid with the 1/3 cup water and remaining 1/4 teaspoon salt in a small pan. Cook over medium-low heat until thickened, 1-2 minutes. Drizzle the sauce over the warm pie before serving.